Slurry hydroprocessing for heavy oil upgrading using supported slurry catalysts

ABSTRACT

A slurry hydroprocessing process (SHP) where a hydrocarbon feedstock is treated at slurry hydrotreating conditions, in the presence of a hydrogen containing treat gas and in the presence of a supported metallic catalyst which is a supported sulfide of a metal selected from the group of non-noble Group VIII metals, Group VIB metals and mixtures thereof where the support is an inorganic oxide and where the catalyst has an average diameter of about 0.5 to about 100 microns to obtain a first product stream comprising the catalyst and a hydroprocessed feedstream; separating the first product into a catalyst-free product stream and a catalyst-containing stream and recycling at least a portion of the catalyst-containing stream back to the hydroprocessing step.

FIELD OF THE INVENTION

[0001] An embodiment of the instant invention is directed to anintegrated slurry hydroprocessing process.

BACKGROUND OF THE INVENTION

[0002] Slurry hydroprocessing (SHP) is a technology capable of providinga low cost means for upgrading heavy crudes. Numerous patents exist thatteach the use of hydroprocessing to obtain upgraded products from heavycrudes.

[0003] U.S. Pat. Nos. 3,622,495 and 3,622,498 describe a slurry processfor effecting the hydroconversion of a hydrocarbonaceous charge stockcontaining sulfurous compounds. The process utilizes finely dividedcatalyst selected from the metals of Group V-B, VI-B or VIII of theperiodic table. Preferred metallic components are vanadium, chromium,iron, cobalt, nickel, niobium, molybdenum, tantalum, and/or tungsten.The Group VIII noble metals are not generally considered for use. Thecatalyst may be combined with a refractory inorganic oxide carrier, butthe process is said to be facilitated when the sulfide of the metal isunsupported.

[0004] U.S. Pat. No. 4,525,267 is directed to a process forhydrocracking hydrocarbons for residuum conversion. At least part of thecatalyst utilized in the hydrocracking is extracted from the reactionzone and subjected to a hydrotreatment regeneration followed by recycleback to the hydrocracking step. The process is said to reduce cokeproduction to a considerable degree.

[0005] While conventional slurry hydroprocessing has met with varyingdegrees of commercial success, there still remains a need in the art forprocesses and slurry catalysts that result in improved yields andselectivity.

[0006] As the supply of low sulfur, low nitrogen crudes decrease,refineries are processing crudes with greater sulfur and nitrogencontents at the same time that environmental regulations are mandatinglower levels of these heteroatoms in products. Consequently, a needexists for increasingly efficient desulfurization and denitrogenationcatalysts.

[0007] What is needed in the art is an improved process and catalystswhich upgrade heavy feeds economically and effectively.

SUMMARY OF THE INVENTION

[0008] An embodiment of the instant invention is directed to a processcomprising the steps of:

[0009] (a) slurry hydroprocessing (SHP) a hydrocarbon feedstock, atslurry hydroprocessing conditions, in the presence of a hydrogencontaining treat gas and in the presence of a supported metalliccatalyst comprising a supported sulfide of at least one Group VIIInon-noble metal and at least one metal selected from the groupconsisting of non-noble Group VIII metals, Group VIB metals and mixturesthereof wherein said support is an inorganic refractory oxide carbon ormixtures thereof and wherein said catalyst has an average diameter ofabout 0.5 to about 100 microns to obtain a first product streamcomprising said catalyst and a hydroprocessed feedstream;

[0010] (b) separating said first product into a catalyst-free productstream and a catalyst-containing stream

[0011] (c) recycling at least a portion of the catalyst-containingstream to said hydroprocessing step (a).

BRIEF DESCRIPTION OF THE FIGURES

[0012]FIG. 1 depicts one possible flow scheme for the instant invention.Feed and slurry catalyst enter the hydroprocessing reactor along withhydrogen. The reactor effluent is then passed to a separator zone thatmay comprises a cross-flow filtration chamber, as shown here, or otherseparation means, where the effluent is separated into a catalyst-freestream and a catalyst-containing stream. The catalyst containing stream,after withdrawal of a purge stream to control solids concentration inthe reactor liquid, is recycled to the hydroprocessing reactor alongwith fresh feed. The catalyst free stream is then separated into gaseousand liquid products. The gaseous products include hydrogen which canthen be recycled to the slurry hydroprocessing reactor.

[0013]FIG. 2 depicts another possible flow scheme where volatiles areremoved before the separation of the first product into a catalyst-freeand catalyst-containing stream.

[0014]FIG. 3 depicts another possible embodiment where the volatiles areremoved from the first product stream during separation into a catalystfree and catalyst containing stream. The effluent from the slurryhydroprocessing reactor can be passed through a cooler (not shown) andintroduced into a gas-liquid separator or disengaging means where thehydrogen gas, along with ammonia and hydrogen sulfide by-products fromthe hydroprocessing reactions, may be separated from the liquid effluentand recycled back for reuse in the hydrogen stream. The recycled gas isusually passed through a scrubber (not shown) to remove hydrogen sulfideand ammonia. This is usually recommended because of the inhibitingeffect of such gases on the kinetics of hydrotreating and also to reducecorrosion in the recycle circuit. Fresh make-up hydrogen can beintroduced into the recycle circuit. The gas-free liquid from thegas-liquid separator then enters a solids separator, or a filter, vacuumflash, centrifuge or the like, in order to divide the hydrotreatingreactor effluent into a catalyst-containing stream and a product stream

DETAILED DESCRIPTION OF THE INVENTION

[0015] An aspect of the instant invention provides an integrated slurryhydroprocessing process which provides a more effective and efficientprocess by improving separation of product from the slurry.

[0016] The process may also include separating said catalyst-freeproduct stream into gaseous and liquid hydrocarbon components prior tosaid step (c).

[0017] A wide range of petroleum and chemical hydrocarbon feedstocks canbe hydroprocessed in accordance with the present invention. Suitablefeedstocks, which will typically contain both nitrogen and sulfur,include whole and reduced petroleum crudes, atmospheric and vacuumresidua, asphaltenes, deasphalted oils, cycle oils, FCC tower bottoms,gas oils, including atmospheric and vacuum gas oils and coker gas oils,light to heavy distillates including raw virgin distillates,hydrocrackates, hydrotreated oils, dewaxed oils, slack waxes,Fischer-Tropsch waxes, raffinates, naphthas, and mixtures thereof.

[0018] The heavy feeds which may be treated in accordance with theteachings herein are heavy feeds, defined as feeds having an API gravityof <10-15° with a viscosity of ≧60 centistokes at 60 C, including heavycrude oils and vacuum resids.

[0019] The light feeds which can be processed herein include feeds suchas kerosene, home heating oil, straight run atmospheric gas oils,straight run vacuum gas oils etc. and mixtures thereof. Typically, suchfeeds will have a boiling point in the range of about 60 to about 1050°F. (about 16 to about 566° C.).

[0020] In an embodiment of the instant invention (illustrated in FIG. 2,a feedstream and slurry hydroprocessing (SHP) catalyst, along withhydrogen are fed to a reactor, which includes an external pump-aroundline and crossflow filter chamber. The crossflow filter chamber, whichoperates at reactor pressure and temperature, consists of a vapor zoneand liquid zone. Hydrogen and gaseous products are removed from thevapor zone to a downstream separator. Upgraded catalyst-free liquid iswithdrawn through the crossfiow filter, and the resultantcatalyst-containing liquid is recycled to the reactor, after removal ofa suitable purge stream to control solids level in the reactor. Therecycle stream can be fed directly to the reactor or premixed with thefresh feed stream. Additionally, fresh catalyst may be used incombination with the recycled catalyst.

[0021] Catalysts which may be utilized in the invention are supportedcatalysts. The supports may comprise inorganic refractory oxides such assilica, alumina and mixtures thereof, carbon and mixtures of carbon andinorganic refractory oxides. The catalyst will preferably comprisesulfides of molybdenum, nickel, tungsten, cobalt, or mixtures thereof.The catalyst will have an average diameter ranging from about 0.5 toabout 100 microns and can be prepared directly from pre-sized inorganicoxide materials or obtained by reducing the size of commerciallyavailable hydrotreating catalysts.

[0022] Preferably, the catalysts will be prepared ex-situ by crushingcommercially available catalysts and catalyst supports to obtain thedesired catalyst diameter. It is believed that the selection and controlof the particle size distribution of the catalyst enhances solid-liquidseparation and significantly improves the hydrodesulfurization process.The ex-situ preparation provides flexibility to control the particlehardness and attrition resistance, intrinsic catalyst activity and othercatalyst properties important to the process performance and physicalseparation.

[0023] An example of a useable catalyst is a supported sulfided materialprepared from a precursor represented by the formula: (X)_(b)(Y)_(c)where X is a Group VIII non-noble metal and Y is a Group VIII non noblemetal or a VIb metal. The molar ratio described as the ratio of b:c is0.1/1 to 3/1, preferably 0.25/1 to 2/1, more preferably 0.35/1 to 1/1,and most preferably 0.4/1 to 0.7/1.

[0024] Another useable sulfided catalyst comprises at least three metalswherein at least one of said metals is a Group VIII non-noble metal andat least one of said metals is a Group VIB metals where the ratio ofGroup VIB metal to Group VIII non-noble metal is from about 10:1 toabout 1:10, supported on an inorganic oxide.

[0025] In yet another preferred embodiment the supported sulfidedmetallic catalyst has a precursor represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z); wherein X is a non-noble Group VIII metal,and the molar ratio of b to (c+d) is 0.1/1 to 3/1; the molar ratio of cto d is ≧0.01/1; and z=[2b+6(c+d)]2.

[0026] In another preferred embodiment of the present invention theGroup VIII non-noble metal is selected from Ni and Co.

[0027] In still another preferred embodiment of the present inventionthe Group VIII metal is Ni, and the X-ray diffraction pattern of thecatalyst is essentially amorphous with crystalline peaks at d=2.53Angstroms and d=1.70 Angstroms.

[0028] In yet another preferred embodiment of the present invention themolar ratio of b to (c+d) is 0.25/1 to 2.0/1 and the molar ratio of c tod is 1/10 to 10/1.

[0029] Desired catalysts that are used to process heavy feeds havemedian pore diameters between 10.0 and 35.0 nm. For distillate boilingrange feeds, preferred median pore diameters are between 12.0 and 20.0nm; and most preferred median pore diameters are between 14.0 and 18.0nm. For heavy feeds, preferred median pore diameters are ≧30 nm. Thesemedian pore diameters are typically determined by Hg porosimetry.

[0030] The process conditions in the hydroprocessing reactor will dependon such things as the particular feed being treated. Such conditions arereadily adjustable by the skilled artisan within the ranges hereintaught. General process conditions for SHP include temperatures of about500° to about 900° F. (about 260 to about 482° C.), preferably about 650to about 850° F. (about 385 to about 454° C.) and most preferably about725 to about 850° F. (about 343 to about 454° C.) and pressures fromabout 300 to about 2500 psig (about 2170 to about 17,339 kPa),preferably about 500 to about 2500 psig (3,549 to about 17,339 kPa) andmost preferably about 800 to about 1000 psig (about 5,617 kPa to about6996 kPa). The hydrogen treat gas rate is suitably about 200 to 2000SCF/B (standard cubic feet per barrel) (36 to 360 m³/m³), preferablyabout 500 to 1500 SCF/B (90 to 270 m³/m³). The residence time issuitably from about 0.5 to 4 hours and preferably about 1 to 2 hours.For heavy feeds, it is preferable to attain about 1025+° F. to 1025−° F.(552+° C. to 552−° C.) conversion of at least about 30%, preferablyabout 40%, and most preferably from about 50 to 60%. Catalystconcentration on feed will range from about 1 wt % to 30 wt %,preferably about 5 to about 20 wt %.

[0031] It is to be understood that the hydroprocessing of the presentinvention can be practiced in one or more reaction zones and can bepracticed in either countercurrent flow or cocurrent flow mode. Bycountercurrent flow mode we mean a process mode wherein the feedstreamflows countercurrent to the flow of hydrogen-containing treat gas.

[0032] The slurry hydroprocessing process of the present invention canbe practiced by introducing a given feedstock into a slurryhydroprocessing reactor. Before being passed to the hydroprocessingreactor, the feed may be mixed with a hydrogen containing gas stream andheated to a reaction temperature in a furnace or preheater.Alternatively, the hydrogen gas can be introduced directly into thehydroprocessing reactor. The reactor contains the slurried catalyst aspreviously described. Recycle of the reactor effluent via a pump isoptional to provide mixing within the reactor zone.

[0033] In the preferred embodiment, the catalyst/solids separation fromthe product oil is accomplished by a cross-flow filtering stepintegrated with a pump around loop in the slurry reactor. In theturbulent cross-flow filtration zone there is minimal build-up of filtercake, which minimizes problems associated with filter binding. Otherestablished separation steps such as gravity settling, centrifugationand other commonly known techniques may also be employed in combinationwith cross-flow filtration to enhance the process performance.

[0034] The most efficient process will employ a catalyst particle sizeand functionality that has been selected for the reactor conversionobjectives and the cross-flow filtering system. The skilled artisan canreadily select such parameters. In the most preferred embodiment,catalyst particle diameters on the order of 0.5 to 25 microns in sizewill be utilized. The performance of the cross-flow filtering step maybe enhanced by the use of filter media aids. These filter media aids canbe specially sized particles in the size range of about 5 to 200 micronsthat are used to pre-coat the filter media surface to enhance filterperformance. Filter design can either be a back-flushed or continuouslypurged configuration.

[0035] The cross-flow filtration step can be either close coupled to thereactor in an external pump around loop or integrated into the reactordesign as a section of the reactor in combination with a pump aroundzone (not shown in the figures).

[0036] In most slurry hydroprocessing operations it is desirable toseparate substantially all of the catalyst from the liquid hydrocarbonproduct. Thus, the separation step is typically carried out underconditions which maximize separation to produce a recyclable activecatalyst product having a maximum concentration which can be pumped orconveyed to the feed. This is typically in the range of from about 5weight percent (“wt. %”) to about 75 wt. %, preferably in the range offrom about 10 wt. % to about 50 wt. %, and even more preferably in therange of from about 15 wt. % to about 35 wt. %. Except for cross-flowfiltration, the separation step may comprise the use of centrifuges,cyclones, filters or even settling and draw-off.

[0037] The following examples are meant to be illustrative and notlimiting.

EXAMPLE 1

[0038] A supported slurry catalyst was prepared by reducing the size ofcommercially available NiMo catalyst (Catalyst A). A sample of CatalystA was wet-ball milled overnight and dried at 100-110° C. for 3-4 hours.After calcining at 400° C. for 3 hours, a fine powdered catalyst samplewas obtained with measured average particle size at 3.6 microns. Priorto hydrotreating tests, it was pre-treated with hydrogen and hydrogensulfide under 1000 psig (6996 kPa) of total pressure (H₂/H₂S=90/10, v/v)at 725° F. (385° C.) for 60 minutes both to sulfide and to activate thecatalyst. Table 1 provides additional physical properties of thiscatalyst. TABLE 1 Physical Properties of Pre-treated Slurry Catalyst APhysical Properties of Slurry Catalyst A Mo, wt % 5.9 Ni, wt % 1.73Surface Area, m²/g 121 Pore Volume, cc/g 0.41 Median Particle Size, μm3.6

EXAMPLE 2

[0039] A typical hydroprocessing experiment involved charging anautoclave with 100 g of resid (ALVR, Brent VR), and appropriate amountof catalyst chosen on the basis of wt % metal on feed. The mixture wasstirred at 1500 RPM at 775° F. (413° C.) under 1000 psig (6996 kPa) ofhydrogen pressure for 2 hours. Hydrogen was flowed through during thetest to maintain an effective hydrogen partial pressure of about 900psig (6307 kPa). The autoclave was then cooled to 300° F. (149° C.) andvented, and the liquid containing the catalyst was discharged. Theproduct was separated by filtration through a two-layer of filtercomposed of one sheet of #2 and one sheet of#3 Whatman filter papers.The solid was washed with toluene and dried under vacuum over night. Theproduct oil was analyzed for metals, sulfur and Microcarbon Residue(MCR). TABLE 2 Mild Slurry hydroprocessing tests of supported slurryCatalyst A. Conditions 775° F. (413° C.), 1000 psig H₂ (6996 kPa), 2hours. The catalyst was charged at 12 wt % on feed equivalent to 0.5 wt% Mo on feed. Total Liquid Arab Light Product Brent Vacuum Resid VacuumResid Quality Feed Cycle 1 Feed Cycle 2 Ni, ppm 10 3.67 27.3 16.0 V, ppm38 1.77 95.7 18.7 S wt % 1.17 0.26 4.18 1.37 MCR wt % 14.9 9.68 24.312.8

[0040] TABLE 3 Limited Catalyst Recycle Tests of the Supported SlurryCatalyst A on ALVR. Conditions: 775° F. (413° C.), 1000 psig (6996 kPa)H₂, 2 hours, the catalyst was charged at 12 wt % on feed for the firstcycle, equivalent to 0.6 wt % Mo on feed. Total Liquid Product ALVRSlurry Hydroprocessing Quality Feed Cycle 1 Cycle 2 Cycle 3 Ni, PPM 27.114.5 20.5 21.6 V, PPM 95.7 18.6 23.9 25.3 S, wt % 4.18 1.44 1.64 1.70CCR, wt % 24.3 13.5 14.5 14.8

[0041] In summary, it has been demonstrated that the supported slurrycatalysts could be utilized to improve the quality of feeds. In the caseof the slurry Catalyst A (Table 2), better upgrading results wereachieved for both Brent VR and ALRV, and HDS was particularly higher dueto Ni components of the catalyst. The recycle test, though not underoptimum conditions, indicated that the supported slurry catalyst couldprovide reasonable recycle activity maintenance (Table 3). In addition,since the supported slurry catalysts are made ex-situ, their particlesize can be better controlled and the size distribution can be madeparticularly narrow, thus providing for better solid-liquid separationrelative to soft, small particle catalysts.

What is claimed is:
 1. A process comprising the steps of: (a) slurryhydroprocessing (SHP) a hydrocarbon feedstock, at slurry hydroprocessingconditions, in the presence of a hydrogen containing treat gas and inthe presence of a supported metallic catalyst comprising a supportedsulfide of at least one Group VIII non-noble metal and at least onemetal selected from the group consisting of non-noble Group VIII metals,Group VIB metals and mixtures thereof wherein said support is aninorganic refractory oxide, carbon and mixtures thereof, and whereinsaid catalyst has an average diameter of about 0.5 to about 100 micronsto obtain a first product stream comprising said catalyst and ahydroprocessed feedstream; (b) separating said first product into acatalyst-free product stream and a catalyst-containing stream; (c)recycling at least a portion of the catalyst-containing stream to saidhydroprocessing step (a).
 2. The process of claim 1 wherein saidhydrocarbon feedstock is selected from the group consisting of heavyfeeds, distillates, asphaltenes, deasphalted oils, cycle oils, FCC towerbottoms, gas oils, hydrocrackates, dewaxed oil, slack waxes, FischerTropsch waxes, raffinates, naphthas, hydrotreated oils and mixturesthereof.
 3. The process of claim 1 wherein said catalyst is selectedfrom a supported sulfided metallic catalyst wherein said metal isselected from molybdenum, nickel, tungsten, cobalt and mixtures thereof.4. The process of claim 1 wherein said inorganic refractory oxidecatalyst support is selected from alumina, silica and mixtures thereof.5. The process of claim 1 wherein said catalyst is a supported sulfidedmaterial prepared from a precursor represented by the formula(X)_(b)(Y)_(c) where X is a Group VIII non-noble metal and Y is a GroupVIII non-noble metal or a VIb metal and the molar ratio of b to c is0.1/1 to 3/1.
 6. The process of claim 1 wherein said catalyst comprisesat least three metals and wherein at least one of said metals is a groupVIII non-noble metal and at one of said metals is a group VIB metalswhere the ratio of group VIB metal to group VIII non-noble metal is fromabout 10:1 to about 1:10.
 7. The process of claim 1 wherein saidcatalyst is prepared from a precursor is represented by the formula(X)_(b)(MO)_(c)(W)_(d)O_(z); wherein X is a non-noble Group VIII metal,and the molar ratio of b to (c+d) is 0.5/1 to 3/1; the molar ratio ofc:d is ≧0.01/1; and z=[2b+6(c+d)]2.
 8. The process of claim 1 whereinsaid Group VIII non-noble metal is nickel.
 9. The process of claim 8wherein said catalyst has an essentially amorphous x-ray diffractionpattern with crystalline peaks at d=2.53 Angstroms and d=1.70 Angstroms.10. The process in claim 1 wherein said separation of said first productinto a catalyst free and catalyst containing stream is accomplishedusing a cross-flow filtering step.
 11. The process of claim 10 whereinsaid catalyst has a particle size of about 0.5 to 25 microns.
 12. Theprocess of claim 10 wherein filter media aids comprising particles inthe size range of about 5 to about 200 microns are utilized.
 13. Theprocess of claim 10 wherein said cross-flow filtering step is integralto said slurry hydroprocessing step.
 14. The process of claim 1 whereinsaid process further comprised separating volatiles from said firstproduct stream prior to said separation step (b).
 15. The process ofclaim 1 further comprising removing gaseous overheads during saidseparation step (b).
 16. The process of claim 15 wherein when saidoverheads comprise a hydrogen containing gas, further comprisingrecycling said hydrogen containing gas to said step (a).
 17. The processof claim 1 further comprising separating said catalyst-free productstream into gaseous and liquid hydrocarbon components prior to said step(c).
 18. The process of claim 1 wherein said supported metallic catalysthas a median pore diameter of between 10.0 and 35.0 nm.